That last point is of critical importance: without knowing the number of impressions authors can expect their book to receive, there is no way of evaluating whether the service justifies the expense.

The Services

Freebooksy / Bargain Booksy

Freebooksy and Bargain Booksy are sister sites. Freebooksy promotes permanently and temporarily free ebooks to their audience of over 230,000 readers, while Bargain Booksy promotes discounted titles to more than 170,000 subscribers. Deal of the Day features are available to distribute ads to a combined audience of Freebooksy and Bargain Booksy subscribers.

Freebooksy and Bargain Booksy recently lowered some of their fees, giving them a competitive edge in several genres.

Requirements: Books must be free for Freebooksy, and between $0.99 and $5.00 for Bargain Booksy. Professional writing, editing, and cover design are required. Amazon reviews are preferred. Deal of the Day ads must be Kindle Countdown deals or must be priced at $2.99, and must have a minimum of 20 4-star reviews on Amazon.

Strengths and Weaknesses: Attractive mailings with a limited number of books. Notification of acceptance usually happens within two days.

Best Categories: Bargain Booksy’s nonfiction categories are great values, particularly the Cooking, Travel, General Nonfiction, and Self Help categories.

BookBub is arguably the best-known service on the market, dominating the ebook discovery landscape with its huge subscriber base. BookBub owes some of this success to a substantial infusion of capital: $3.8 million in funding in 2014, plus another round of $7 million in 2015.

BookBub promotions have limited space and high demand: only 10-15% of BookBub applicants are accepted out of 200-300 submissions daily.

In addition to its genre-based mailings, the site offers distribution to a regional subset of its list, for either US distribution or international distribution (UK, Canada, India, and Australia). These options are available at a reduced price (approximately 82% of full price for US, 24% of full price for international), however, they may also reduce the chances of your promotion being selected.

Requirements: Books must be discounted by at least 50%. Discounts (other than permanently free) must be limited-time offers, and must be the best price available in the last 90 days. Short stories and novellas are not accepted. Eligible books must meet length requirements which vary by the book’s type. Books will not be featured more than once every 6 months.

Strengths and Weaknesses: Massive subscriber base. Best median value for free books; ties with Fussy Librarian for $0.99 books. High demand and stringent quality standards mean low acceptance rates for applicants. BookBub’s wider distribution comes with a high price tag in popular genres, and titles priced higher than $0.99 generally offer a lower return on investment.

Formerly BookBlast, BookSends operates its own discovery service as well as providing lists to other services like EReaderIQ (profiled below).

BookSends has an unusual pricing model in that ads for $0.99 books are priced lower than ads for free books.

Requirements: Five reviews with a high average, sale price under $3.00, and discounted to at least 50% of full price. Novellas and collections of short stories are unlikely to be accepted as paid books.

Strengths and Weaknesses: Generally good reports of high downloads and sales. BookSends may ask applicants to reschedule rather than rejecting them for scheduling reasons. Authors can use affiliate links on free book promotions. High CPM (second only to EReaderIQ, a BookSends partner).

Best Categories: At the $0.99 price point, Children’s Books, Teen/YA, and Mysteries/Thrillers are BookSends’ best values.

Fussy Librarian launched in 2013 with the promise of recommendations tailored to the individual reader. Subscribers can choose from 11 nonfiction and 29 fiction categories; specify their preferred language (English, Spanish, Hindi, Portuguese, German, French, Japanese, Russian, or Italian); and can filter books by their level of profanity, violence, and sexual content.

Fussy Librarian has approximately 121,000 subscribers. Authors can promote their book to a second genre list at half price.

Requirements: Books must be $5.99 or less on the day of the promotion, and must have either 10-19 reviews with a 4.0 rating on Amazon (may be split across multiple stores), or 20+ reviews with a 3.5 rating. Only Amazon reviews are accepted.

Strengths and Weaknesses: Best median value for books priced over $0.99 and over. 50% discount when promoting in a second category. Content filters allow more precise targeting. Most approved books are notified within 24 hours.

Robin Reads lists books which are free or $0.99 and sends out daily email bulletins to approximately 120,000 subscribers. (Although the site does not separate genres in its mailers, it does provide statistics for its readers’ genre preferences. Price comparisons are based on these figures.)

Requirements: Books must be well-formatted ebooks priced at free or $0.99. No minimum length requirement, but full-length books are given priority over shorter works. Professional presentation. No minimum number of reviews required.

Strengths and Weaknesses: Same fee for free and $0.99 books. Comparatively poor CPM on smaller genre lists. Less attractive mailers.

EReaderIQ is an ebook tracking service which allows users to monitor authors, titles, or an Amazon wish list, and to receive notifications when the prices of their items change. They also maintain an ebook discovery service that combines its own lists with partner BookSends’ database to reach more than 150,000 subscribers.

Requirements: Identical to BookSends. Five reviews with a high average, sale price under $3.00, and discounted to at least 50% of full price. Novellas and collections of short stories are unlikely to be accepted as paid books.

Strengths and Weaknesses: Charges less for books at the $0.99 price point. In general, EReaderIQ charges more than its partner BookSends, but the increase in the number of subscribers doesn’t always match the increase in the fee.

BookGorilla’s categories are the most detailed on the market, offering a menu of more than 260 subcategories of fiction and nonfiction to its 350,000-member audience. Subscribers receive ebook listings tailored to their preferences.

Requirements: Books must be priced below $3.99. Books over $1.99 are a minority. Discounted prices are not a requirement. Books with less than a 4-star rating or fewer than 5 reviews on Amazon are likely to be rejected. Book ads may only run once in a 14-day period.

Pricing and Value

For each genre below we have evaluated four price brackets — Free, $0.99, $1.99, and $2.99 or higher. Each tab lists the services from best to worst value, determined by the cost to reach 1,000 subscribers (CPM). The higher on the list an option is, the better its value.

Although most services assign a genre to your book, they may honor requests for a specific genre. Only genres which have comparable categories among two or more services are shown.

Prices, categories, and subscriber counts were gathered on May 24, 2016. Consult the companies’ websites for the most recent details.

$1.99 Books

$2.99 Books

Service

Category

Reach

Cost

CPM

BookGorilla

Crime Fiction

185,500

$ 100.00

$ 0.54

BookBub

Crime Fiction

3,640,000

$ 2525.00

$ 0.69

BookBub offers the superior value for free Crime Fiction promotions, but low acceptance rates and a steep price tag will put it out of reach of many authors. Although BookGorilla is not a solid value for free books, it matches Bookbub’s value at the $0.99 price point and exceeds it at the $2.99 – $3.99 price range (the highest price BookGorilla will accept).

$1.99 Books

$2.99 Books

Service

Category

Reach

Cost

CPM

Bargain Booksy

Sweet Contemporary Romance

116,600

$ 70.00

$ 0.60

BookGorilla

Romance

101,500

$ 100.00

$ 0.99

EReaderIQ

Romance

86,000

$ 180.00

$ 2.09

Booksends

Romance

44,500

$ 120.00

$ 2.70

In general Romance, BookGorilla offers a superior value for titles priced at $0.99 and below, while Bargain Booksy tops the $1.99 and over brackets. However, see Contemporary Romance and other subgenres below which may have a better CPM than the general category.

$1.99 Books

$2.99 Books

Service

Category

Reach

Cost

CPM

Fussy Librarian

History

24,721

$ 10.00

$ 0.40

BookBub

History

1,620,000

$ 1325.00

$ 0.82

BookGorilla

All Nonfiction – History

70,000

$ 75.00

$ 1.07

Conclusion

For free books, BookBub remains the gold standard for ebook discovery services. Its gargantuan membership places it in a weight class of its own, and it is arguably the most popular of the services in our roster. That popularity also makes it one of the most difficult service to enter; high demand and increasing interest from traditional publishers leads to heavy competition for relatively few slots. But if the steep price tag is within your means and you can secure a spot in their schedule, BookBub offers a solid return on your investment.

For paid books (particular books priced at $2.99 and over), the clear champion is The Fussy Librarian. Fussy Librarian has a much smaller membership, but its correspondingly lower fees do not vary with the price of the book. With superior CPM for higher-priced books and the best CPM across nearly every fiction category, Fussy Librarian presents an outstanding value for a surprisingly low price.

Bargain Booksy ranks moderately well in fiction genres, particularly in the higher price brackets. However, Bargain Booksy really shines in nonfiction categories, where it sits at the top of most rankings. Freebooksy does not fare quite as well as its sister site, generally resting in the lower half of its genres. The popular categories of Mystery, Cozy Mystery, and Thrillers are a notable exception.

Book Gorilla performs erratically overall, offering moderate value in most categories, and bafflingly uncompetitive pricing in others. Book Gorilla is a good investment in categories like Mystery and Thriller, but compare pricing and consider alternative subgenres to obtain the best value.

Robin Reads represents fair-to-poor value in its categories, with the median cost per thousand impressions weighing in at over $1.00. Robin Reads’ best category is Mystery, placing 4th out of the 6 companies represented in that genre.

BookSends / EReaderIQ are listed jointly here, as their shared membership and uniformly high price consistently place last in the rankings — sometimes with a CPM as much as 10 times higher than the closest competitor. Without exception, there are more cost-effective options for promoting your books.

Over To You

Which of these companies have you used to promote your books? What other ebook discovery services have you had success with? Let us know in the comments below.

About John Doppler

From the sunny California beaches where he washed ashore in 2008, John Doppler scrawls tales of science fiction, urban fantasy, and horror -- and investigates self-publishing services as the Alliance of Independent Authors's Watchdog. John relishes helping authors turn new opportunities into their bread and butter and offers terrific resources for indie authors at Words on Words. He shares his lifelong passion for all things weird and wonderful on The John Doppler Effect.

42 Responses to 8 Ebook Discovery Services Compared

Useful guide, but inevitably hugely out of date now. (Not really a criticism as we could hardly expect it to be exactly the same two years on)
Nevertheless, I will be making use of some of the information given.

John, thank you for putting in the work to help authors learn more about the promotions sites we use. I find this information valuable and will be taking it into consideration when I schedule my next promotion. Again, thank you.

Thank you sir, this is a well-prepared and helpful article, especially for struggling writers of independent press. I will share it my brother who is who is working on his first book, and give the link to others.

Wow, John. I’m blown away from the work you put into this. Thank you so much! Learned a lot from this and also from replies. I will definitely share on my writer’s blog. Only thing I need is a definition of CPM. Thanks!
Christine

Cost per thousand (CPM) is a marketing term used to denote the price of 1,000 advertisement impressions on one webpage. If a website publisher charges $2.00 CPM, that means an advertiser must pay $2.00 for every 1,000 impressions of its ad. The “M” in CPM represents the Roman numeral for 1,000.

Hi John, thanks for taking the time and effort to assemble your list. I think there might be a couple of things you would be interested to know or that you’re not properly considering when evaluating our site. First of all, BookSends and EreaderIQ do not have any reader overlap. Unlike most other sites, we regularly prune our lists so that we’re giving authors a strong representation of our *active* subscribership. After all, subscribers who never open emails are worthless to authors. The entire concept of eCPM is a poor metric for authors to use in this regard. What matters is how many people actually open an email and take action on books, not how many people signed up for a list, clicked Spam 6 months ago, and are still being presented to authors as viable targets of the mailings. If I had a list of just 100 readers who would buy one book every day at $2.99, charging $75 for that list might have a horrible eCPM but I’m pretty sure every author would feel it was worthwhile. At BookSends, we try to give authors a better idea of how many readers their book will actually be exposed to. Thanks!

The ability for authors to use affiliate codes (in a way compliant with Amazon TOS as all clicks are routed through websites) also deserves much more attention. We see authors earn over $200 from just one inclusion of their affiliate code in an ad, and many see at least half the ad cost back from affiliate earnings, if not the entire thing. That’s why authors earn more from free promotions with us than any other site. We think outside the box when it comes to increasing returns for authors, and we’re glad so many appreciate that and keep coming back and back.

John, This is so helpful and informative! My novel (women’s fiction) will be released next week through Kindle Press and I am headed over to the Fussy Librarian! Thank you for taking the time to compile all this info and share it so generously!

Thank you, John Doppler. I loved the stats you provided. One item I’d refer to is BookSends allowing authors to use their affiliate codes on their books. And now on both free and priced units. But Amazon told me last week in an online chat that using affiliate codes on any book in a newsletter/email promo is against their TOS. As for all of the other data, I’ve always had an ROI on Bookbub promotions. I often have not seen the ROI I’d anticipated on the other seven. Now, because of your brilliant deductions, I know why. Sweet romance is not among many promoter’s top tier audience today–very good data to keep in mind when stacking promotions. I’m also curious why Michael Gallagher’s fkbt did not make your list for comparison.

It is against Amazon’s terms to use an affiliate code directly in an email (or any form that’s not attributable to a website, such as shortlinks, QR codes, and printed material like bookmarks or flyers).

However, it is legal to provide a link to a website, and from there, redirect the user to the Amazon page with an affiliate code. This is the technique BookBub now uses to get around the prohibition on emailed links.

That rule has tripped up a number of email-based services this year.

Regarding Free Kindle Book and Tips, Michael let me know that they don’t track stats for individual genres, so there wasn’t a basis for a fair comparison in this case.

This list is useful, but email one-off promotions are only one segment of book discovery. Perhaps the title of this piece might be “8 Email Ebook Discovery Services” instead, to be more accurate?

BooksGoSocial.com, which I founded three years ago, provides its main reach through social media, Twitter & Facebook, to enable discovery over the long term, to over 709,193 followers.

The idea that email is the only discovery option for authors is simply incorrect. There are other social media services as well as BooksGoSocial providing social media discovery services.

Secondly, short term one-off book promotion spikes are useful and can have a tailing effect, but in our view a longer term daily increase in sales, moving an author from average sales of one book a day to average sales of ten books a day, for instance, will have a greater sustained impact on author earnings.

Well presented, well priced books in popular genres can achieve email driven spikes in sales, and be supported with longer term social discovery services, reducing the need for authors to spend valuable time sustaining their social media presence.

Sustained increased sales, through low priced, long term social book discovery, is a real alternative to the services you describe.

We are, in fact, so confident of our ability to help authors, we offer a 60 day money back guarantee. If a book fails to sell at any of the email book discovery services you reviewed the author is unlikely to even get a reply if they ask for their money back.

Herding authors towards one off promotions with no money back guarantee is a limited approach to ebook discovery.

“8 Email-Based Genre-Specific Ebook Discovery Services Compared” was a bit too wordy for a title, but it certainly wasn’t my intention to imply that email was the only option — it’s just the focus of this particular analysis.

Data for other channels such as apps, websites, social media, etc., is harder to come by, and makes for a trickier comparison, but that project is on my To Do list.

Thanks, Mark! Neither of those services qualified for this comparison, but I’ve heard positive reviews from clients of both services. I plan to take a closer look at both.

I’ll have to say that BK Knights’ Fiverr-based service is definitely one of the more unusual ones out there! It makes me curious why they haven’t made the transition to a business with a more solid web presence.

Thanks so much for taking the time to gather the info, break it down into categories, and share all of it with writers. I could not ask for a better comparison. Now, to pick the one that is right for me!
: )

Many thanks for a great post, John – and good to see stats for children in here. I will try to break into BookBub again on the basis of this – especially now my books are on all platforms again. Very useful.

One thing I’m not clear on in the early part is when you talk about the number of Amazon reviews needed. Does this mean across both UK and USA? For example, I have 43 reviews for The Secret Lake in the UK but only 15 in the USA. And (more problematically) 16 for Eeek! in the UK but only something like 4 in the USA. If sites like BookBub only take account of US reviews then raising the profile in the USA of a book that has had a good number of 5-Star reviews in the UK becomes problematic… I know you did specify one site that counts reviews across more than one Amazon store, but does that mean that by default where you don’t mention this that site is only looking at US reviews?

This was very helpful, particularly in giving the comparisons for the specific genres and sub-genres. So often we are left to go by the anecdotal evidence of other authors which can be helpful. But unless our books are identical in market, its hard to judge whether or not that site will work for us since milage varies so much. 🙂

Staggered that Ereader News Today didn’t rate a mention. Outside of BookBub it leaves anything else for dead both in cost and coverage. I’ve used both and the ENT cost per download is significantly less than BB’s. You get more downloads with BB but ENT is far better value.
Still pinching myself that ENT didn’t rate a mention. Its email subscriber list would probably exceed the aggregate of all other sites mentioned above (excluding BB).

Hi Peter,
Unfortunately, ENT does not post their statistics, and they did not respond to requests before the article was published. Without that information we cannot make a fair comparison to the other services.

If they provide that information (and I hope they do), I’ll be happy to include them in the next iteration of this article.

[…] them properly. What gems might I find by subscribing as a reader? An excellent article by the Alliance of Independent Authors compared them in terms of value for advertisers, and rated Bookbub, Fussy Librarian and Bargain […]

[…] wondered where to advertise your KDP free days or any other book promotion? John Doppler from SelfPublishingAdvice compared mailing lists, readership numbers, and the cost for e-book discovery services: “Free […]